src/main/java/de/uapcore/lightpit/dao/ModuleDao.java

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * 
 * Copyright 2018 Mike Becker. All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
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 *   1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
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 *   2. Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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package de.uapcore.lightpit.dao;

import de.uapcore.lightpit.LightPITModule;
import de.uapcore.lightpit.entities.Module;

import java.sql.*;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class ModuleDao {

    /**
     * Maps database columns to POJO fields.
     *
     * @param result the database result set
     * @param mod    the POJO
     * @throws SQLException
     */
    protected void mapColumns(ResultSet result, Module mod) throws SQLException {
        mod.setModID(result.getInt("modid"));
        mod.setClassname(result.getString("classname"));
        mod.setVisible(result.getBoolean("visible"));
    }
            
    
    /**
     * Must return a prepared statement for a single object query with the specified properties.
     * 
     * <ul>
     * <li>Parameter 1: classname</li>
     * <li>Result field 1: visible</li>
     * </ul>
     * 
     * @param conn the connection to use
     * @return the prepared statement
     * @throws SQLException 
     */
    protected PreparedStatement moduleCheckStatement(Connection conn) throws SQLException {
        return conn.prepareStatement("SELECT visible FROM lpitcore_module WHERE classname = ?");
    }
    
    /**
     * Must return a prepared statement for insertion with the specified properties.
     * 
     * <ul>
     * <li>Parameter 1: classname</li>
     * <li>Parameter 2: visible</li>
     * </ul>
     * 
     * @param conn the connection to use
     * @return the prepared statement
     * @throws SQLException 
     */
    protected PreparedStatement moduleInsertStatement(Connection conn) throws SQLException {
        return conn.prepareStatement("INSERT INTO lpitcore_module (classname, visible) VALUES (?, ?)");
    }
    
    /**
     * Synchronizes a set of registered module classes with the database.
     * 
     * Inserts module classes which are not known to the database and sets them to be visible by default.
     * Module classes known to the database, which are not in the given set, are ignored.
     * 
     * @param conn the connection to use
     * @param moduleSet the module set to synchronize
     * @throws SQLException
     */
    public final void syncRegisteredModuleClasses(Connection conn, Set<Map.Entry<String, LightPITModule>> moduleSet) throws SQLException {
                
        PreparedStatement
                check = moduleCheckStatement(conn),
                insert = moduleInsertStatement(conn);
        insert.setBoolean(2, true);
        // update/delete not required, we do this in the module management UI

        for (Map.Entry<String, LightPITModule> modEntry : moduleSet) {
            if (modEntry.getValue().systemModule()) continue;

            check.setString(1, modEntry.getKey());
            try (ResultSet r = check.executeQuery()) {
                if (!r.next()) {
                    insert.setString(1, modEntry.getKey());
                    insert.executeUpdate();
                }
            }
        }
    }

    /**
     * Returns a list of all modules known by the database.
     * 
     * Keep in mind, that system modules are never known to the database.
     * 
     * @param conn the connection to use
     * @return a list of all modules known by the database
     * @throws SQLException 
     */
    public List<Module> listAll(Connection conn) throws SQLException {
        List<Module> list = new ArrayList<>();
        try (Statement stmt = conn.createStatement();
                ResultSet result = stmt.executeQuery("SELECT * FROM lpitcore_module")) {
            while (result.next()) {
                final Module mod = new Module();
                mapColumns(result, mod);
                list.add(mod);
            }
        }
        return list;
    }
}